Wearable device comprising one or more impact sensors

ABSTRACT

Wearable device having one or more impact sensors and at least one unit transmitting a detected signals to a remote station, the device being composed of an inner glove wearable under a martial art glove.

The present invention relates to a wearable device comprising one ormore impact sensors and at least one unit transmitting the detectedsignals to a remote station.

This type of devices are known and used for measuring performances ofathletes, above all in the martial art field.

The U.S. Pat. No. 5,723,786 describes a boxing glove wherein an impactmeasuring device is incorporated which comprises a fluid bag in theimpact area of the glove, which bag is connected by a tube to a pressuresensor provided in the cuff.

The U.S. Pat. No. 4,761,005 describes a device for generating an analogoutput signal indicative of an impact to a transducer.

The transducer may be mounted on protective equipment used in variousmartial art fields, such as boxing gloves, shin guards, vests and it isof the piezoelectric type and it is indicative of the amount ofdeformation.

The transducer is composed of a piezoelectric film coupled to adeformable material, or it is inserted between two layers of deformablematerial, and the output signal is generated on the basis of the impactson the deformable material.

The transducer may be connected to a remote receiver and transmitter forproviding an indication of the impact to a remote station.

Therefore the known devices are part of the protective equipment of theathlete, for example they are composed of boxing gloves.

This condition has some drawbacks.

Firstly the boxing glove by its nature is subjected to many andrepetitive stresses even of considerable level and therefore it issubjected to wear above all in the external part which can be subjectedto tearing or other similar damages.

Therefore, over time, the boxing glove has to be replaced, and all thesensor part incorporated therein has to be necessarily replaced with it.This causes the use of such type of devices to be expensive, whichcurrently are not widely spread and do not have a suitable success inthe market.

Secondly, it is not rare for an athlete to perform more than one martialart, and for each martial art a different type of boxing glove isnecessary.

In this case, in order to use the same type of sensors in the differentmartial arts, the athlete must necessarily have a plurality of specificgloves, each pair of gloves comprising the same type of sensors andcomponents, with a substantial increase in costs and a uselessredundancy in the components themselves.

Moreover the known devices have a single impact sensor and thereforethey do not allow the type of impact to be finely detected, providingmore detailed information above all as regards the geometry of theimpact.

The fact of providing a single sensor, moreover, can lead toinaccuracies in the measurement, for example a wrong calibration or dueto too much high tolerances in the detection.

Therefore there is the unsatisfied need in the prior art for a deviceallowing costs to be considerably reduced, which is usable in differentmartial arts and that contemporaneously guarantees a good accuracy andreliability of the impact measurement.

The document US 2006/047447 A1 describes a gauze bandage provided withmonitoring components, that wraps the hand of the athlete. Thisarrangement does not allow for a correct positioning of the sensors,because the gauze bandage needs to be wrapped around the hand of theathlete and a different tensioning of the bandage during the wrappingcan lead to completely different positions of the sensors. The athletemust take an excessive cure on positioning the bandage, because anincorrect positioning of the sensor can lead to results that aredistorted, even to a great extent.

The present invention overcomes the drawbacks of the known devices byproviding a device such as described hereinbefore, which is composed ofan inner glove wearable under a martial art glove.

Thus the inner glove or glove liner can be used with different types ofgloves or boxing gloves.

This allows the same inner glove to be reusable even when the glove hasto be replaced, and it allows only one inner glove to be used withdifferent specific gloves for different martial arts.

The inner glove allows for a univocal and precise positioning of thesensors, when the athlete wears it.

The term inner glove means a glove with a thickness lower than 4 mm,composed of stretch or non-stretch fabric, made of any material, such ascotton or synthetic fibers.

It is possible to use at least partly engineered fibers, whichincorporate several types of sensors therein.

According to one embodiment one or more inertial sensors are provided.

The inertial sensors can comprise accelerometers and gyroscopes incombination or as an alternative with each other.

This allows speeds and linear and angular accelerations to be measuredwithout the need of an external reference.

According to a further embodiment there are provided one or morebiometric sensors.

Biometric sensors can be of any type, for example heart beat sensors,body temperature sensors, blood pressure sensors, oxygen saturationsensors, perspiration sensors.

Usually the athlete under the martial art gloves wears, as analternative to the inner glove, wraps which are wrapped around the handand the wrist.

Therefore biometric sensors cannot be mounted directly on the glove,since the inner glove or the wraps prevent them from directly contactingthe athlete skin.

This would make it necessary to use wires for reaching an area of theforearm not covered by the wraps or by the inner glove, such area beingclearly disadvantageous with respect to the wrist for example in thecase of detection of the heart beat.

In the device of the present invention, on the contrary, biometricsensors are advantageously arranged on the inner glove, which is indirect contact with the athlete skin, guaranteeing an accurate detectionof the biometric values desired to be monitored.

According to one embodiment, one or more of the fingers of the innerglove are truncated, such that the inner glove, in the worn condition,covers only the first phalange of one or more of the correspondingfingers of the user.

This strengthens the flexibility concept characterizing the device ofthe present invention, since thus the inner glove can be worn with theglove of any martial art, also those martial arts that provide anopen-fingered glove, such as for example MMA (Mixed Martial Arts).

According to a further embodiment said impact sensors are of thepiezoelectric type.

As an alternative or in combination impact sensors can be of thecapacitive type or of another type, for example strain gauges.

According to a further embodiment there is provided a plurality of saidimpact sensors, which impact sensors are arranged in such a manner toform an array.

Thus information about the impact are detected from different positionssuch to perform more accurate evaluations on the impact and such to havea more accurate estimation of the detected values and of theircorrectness.

According to an improvement there are provided one or more impactsensors at the forefinger, middle finger, ring finger and little fingerrespectively.

Thus it is possible to cover with the sensors a detection area that isdistributed on all the impact area of the fist.

It is further possible to make an evaluation of the impact for eachindividual finger, allowing the geometrical characteristics of theimpact to be reconstructed.

In a further improvement there are provided three sensors for each oneof said fingers.

Thus the array of sensors is composed of 12 sensors, although more orfewer sensors are possible, also distributed in a non-homogeneous manneron the fingers.

It has been found that an array of 12 sensors has good dimensions to bemounted on the inner glove and to guarantee a sufficiently detaileddetection of the impact.

In an advantageous embodiment only two impact sensors are provided foreach finger.

Advantageously there are provided four sensors on the knuckles, that ison the area more involved in the impact.

In one variant embodiment there are provided 8 sensors, two sensorsbeing provided for each finger.

In a further embodiment, at least one sensor is placed on the gloveportion corresponding to the back of the hand.

This allows hits on the back of the hand to be detected and measured.

According to a further embodiment the unit transmitting the detectedsignals is set such to transmit the signals to the remote station inreal-time.

This has the great advantage of allowing the detected signals to be usedfor supplementing television shooting of the matches with real-time dataof the athlete performances.

The present invention further relates to a wearable device comprisingone or more impact sensors and at least one unit transmitting thedetected signals to a remote station, which device comprises a pluralityof said impact sensors, which impact sensors are arranged such to forman array.

The device advantageously is a part of the protective equipment of anathlete, such as for example boxing gloves, shin guards, vests,knee-pads, elbow guards, helmets, shoes.

According to one embodiment the device is composed of a glove or aninner glove and it comprises one or more of the characteristics listedabove. Even if the characteristics listed above are described withreference to an inner glove, they can be considered valid for a glove ora boxing glove.

The signals generated by the accelerometer can be used to obtain anestimation of velocity in the three directions. Theoretically it ispossible to obtain the velocity from the acceleration, by performing thefollowing integration:

v(T) = ∫_(−∞)^(T)a(t)t

However, the measures of the acceleration generated by the accelerometerhave some offsets that are not constant in time and that would lead theintegral to diverge. In order to obviate to this problem, the integralis approximated with a low-pass filter, so to diminish the driftproblems. Furthermore, in order to diminish these effects at lowfrequencies, also a high-pass filter is applied.

Anyway, this estimation is not sufficiently reliable for the hand'smovement during a hit. Without an estimation of the trajectory in thethree dimensions, in fact, it is not possible to remove from theacceleration the components due to the centrifugal forces and the changeof gravity given by changes of orientation of the device.

An accurate estimation of the trajectory would be possible only with anIMU with nine degrees of freedom, which would increase exaggeratedly thecost, weight and complexity of the device.

In order to obviate to these problems, the present invention relate alsoto a method for estimating the velocity starting from the velocity lostduring the hit. Thanks to this approach, it is possible to ignore thevelocity variations before the impact and, therefore, also the problemsrelated to them.

This method of measuring the power of an impact of a wearable devicecomprising one or more impact sensors and at least one accelerometer,comprises the following steps:

-   -   a) acquiring signals of acceleration from the accelerometer;    -   b) obtaining the velocity vector along a predetermined direction        by integrating the acceleration signals;    -   c) obtaining the force vector of the impact from the impact        sensors, said sensors being positioned in such a way that the        force vector is along the said predetermined direction of the        velocity vector;    -   d) calculate the power of the impact as the dot product of the        force vector and the velocity vector.

The energy of each impact is also calculated from the power.

According to an advantageous embodiment the velocity vector is takeninto account for the calculation of the power of the impact only in thetime period when said velocity is decreasing during the impact.

This allows to overlook the velocity before the impact, and to obtain amore precise calculation.

According to an embodiment, a low-pass filter is applied to theacceleration signal before step b).

According to a further embodiment, wherein a high-pass filter is appliedto the acceleration signal before step b).

These and other characteristics and advantages of the present inventionwill be more clear from the following description of some non limitativeembodiments shown in the annexed drawings wherein:

FIGS. 1 to 3 are different views of the device;

FIG. 4 is a functional block diagram of the device;

FIG. 5 shows the measured velocity;

FIGS. 6 to 8 show the velocity, force and power of an impact;

FIG. 9 shows the calculated energy.

FIG. 1 shows the wearable device of the present invention, which iscomposed of an inner glove 1 wearable under a martial art glove.

The inner glove 1 is shown in the worn condition and with the user handclosed in a fist.

The fingers of the inner glove 1 are truncated, such that in the worncondition the inner glove 1 covers only the first phalange of the user'sfingers.

As an alternative it is possible to provide an inner glove withnon-truncated fingers, or with the fingers truncated such to cover alsothe second phalange of the user's fingers.

The inner glove 1 is composed of stretch or non-stretch fabric, made ofany material, such as cotton or synthetic fibers.

On the inner glove 12 impact sensors 2 are fastened arranged such toform an array.

There are provided three impact sensors 2 at the forefinger, middlefinger, ring finger and little finger respectively, such to define adetection area that is distributed all over the impact area of the fist,one sensor of which being placed on the knuckle.

According to one embodiment the impact sensors 2 are of thepiezoelectric type, but they can be, as an alternative or incombination, force sensing resistors (FSR) or of the capacitive type orof other type.

FIG. 2 shows a view of the back of the hand with the inner glove 1 inthe worn condition, wherein the array of impact sensors 2 is visibleplaced on the truncated fingers of the forefinger, middle finger, ringfinger and little finger.

The device comprises an inertial sensor 3 or inertial measurement unit,which can comprise one or more accelerometers and/or gyroscopes incombination or as an alternative to one another.

For example it is possible to provide three accelerometers and threegyroscopes in order to produce a three-dimensional measurement of thelinear and angular accelerations.

FIG. 3 shows a view of the hand palm with the inner glove 1 in the worncondition, wherein a biometric sensor 4 is visible, advantageouslyplaced in the wrist area.

It is possible to provide only one or more biometric sensors, which canbe of any type, for example heart beat sensors, body temperaturesensors, blood pressure sensors, oxygen saturation sensors, perspirationsensors.

Sensors 2, 3 and 4 are connected to a central processing unit 5 whichcomprises a unit transmitting the detected signals to a remote station.

The processing unit 5 preferably is composed of a flexible electroniccard, in order to be better secured to the inner glove 1, which acts asa support, which electronic card comprises a microprocessor and aplurality of electronic components conditioning the input signals.However, in a different embodiment the electronic card is non-flexible.

All this can be covered by a layer of resin or the like such to preventcomponents from being unwelded during the use.

As an alternative or in combination a curing process can be used forinsulating the components.

The connection is guaranteed by electric wires, preferably housed intocoulisses formed on the inner glove 1.

Advantageously, the wires have a zigzag pattern such to have a lengthenough for guaranteeing a connection without tearing or damages for anytype of deformation and elongation to which the inner glove 1 or a partthereof is subjected during the use.

The processing unit 5 is powered by an electric energy source,preferably a battery.

The battery can be housed in a pocket formed in the inner glove 1 whichcan be accessed from the outside to allow the battery to be replacedonce it is depleted.

As an alternative the battery is rechargeable, for example it iscomposed of a lithium-ion battery or a lithium-ion polymer battery or anickel-metal hydride battery (NiMH) or another type, there beingprovided a recharging circuit comprising a connector to an externalpower supply, such recharging circuit being outside of or integratedwith respect to the processing unit 5.

As an alternative, the recharging circuit can comprise an inductivecharging system, which comprises a receiver coupled to the battery andwhich is arranged to communicate with a transmitter coupled with anexternal electric source. Both the transmitter and the receiver areprovided with one or more coils, in order to perform inductively thiswireless energy transfer, by simply bring near the transmitter and thereceiver. Preferably the standard Qi is used. However, other standardsor protocols can be used.

The device can be switched on or off by means of a switch. The switchcan comprise a very thin button, a tactile button, which is sensitive topressure like the pressure sensors, or a magnetic switch, which can beactivated or deactivated by means of a small magnet.

In another embodiment, the device is switched in stand-by consequentlyto an inactivity period as detected by the accelerometer, and can beswitched on again once a movement is detected.

FIG. 4 shows a functional block diagram of the device, wherein impactsensors 2, inertial sensors 3 and biometric sensors 4 are visible,connected to the central processing unit 5.

The data detected by the different sensors are sent to the centralprocessing unit 5, which comprises a unit 51 transmitting the detectedsignals to a remote station.

The unit 51 transmitting the detected signals is configured such totransmit the signals to the remote station in real-time, such that thedata can be displayed during television live broadcasts of the matches.

The communication between the unit 51 transmitting the detected signalsand the remote station can occur according to any protocol, preferablyaccording to the ZigBee protocol or Bluetooth protocol.

The central processing unit 5 comprises an average unit 50, whichaverages two or more of the signals detected by the impact sensors 2 andit sends the calculated values as an alternative or in combination withthe signals detected by the impact sensors 2.

In one embodiment all the signals detected by the impact sensors 2 areaveraged for obtaining a single calculated signal indicative of all theimpact sensors 2.

According to a variant embodiment the signals about each finger areaveraged, therefore 4 signals are obtained indicative of each finger.

The central processing unit 5 further comprises a unit measuring theresidual charge of the battery 54, which generates an alarm signal whenthe residual charge goes below a predetermined threshold.

The signal can be sent to the remote station from the unit 51transmitting the detected signals or it is possible to providesignalling means for the user, such as a buzzer or a LED.

The central processing unit 5 comprises a patient health alarm unit 55,which compares the signals received from the biometric sensors 4 withthreshold values, which can be predetermined or set by the user, and itgenerates an alarm signal if the detected values exceed the thresholdvalues.

The central processing unit 5 further comprises a unit 56 recognizingthe given punch, which processes the signals generated by the inertialsensors 3 for defining known patterns referable to particular moves ofthe athlete.

The data are further compared with the signals coming from the impactsensors 2 in order to estimate the punch given by the athlete.

All the received or generated signals can be stored by the centralprocessing unit in a local storage unit 52, which is accessible by meansof an input/output unit 53, such as a USB port or a slot for a flashcard or similar non volatile storage devices.

The signals generated by the accelerometer can be used to obtain anestimation of velocity in the three directions. The velocity is obtainedfrom the acceleration, by performing the following integration:

v(T) = ∫_(−∞)^(T)a(t)t

and applying a low-pass filter and a high-pass filter.

Furthermore, the velocity is estimated starting from the velocity lostduring the hit. Thanks to this approach, it is possible to ignore thevelocity variations before the impact and, therefore, also the problemsrelated to them.

FIG. 5 shows the velocity measured for two impacts. As can be seen, thevelocity is always ignored except for during the impacts.

Once the velocity is calculated from the acceleration, as explainedabove, it is possible to calculate and plot the power of an impact,using the following formula:

P(t)={right arrow over (F)}(t)×{right arrow over (v)}(t)

where X is the dot product of the force vector and the velocity vector.

FIGS. 6, 7 and 8 show respectively the velocity, force and power of thesame impact, as measured and calculated above.

The direction of interest is obviously that with versor coming out fromthe fingers. The force measured by the sensors, thanks to theirpositioning, is already the component in that direction, and it will besufficient to multiply it with the direct velocity in the same way toobtain an estimation of the power.

The energy is linked to the power by the following integration:

E∫_(t1) ^(t2) P(t)dt

where t1 and t2 are the start and end instants of the hit.

In this way the energy of every single hit is calculated from the power,as can be seen in FIG. 9.

The invention claimed is:
 1. A wearable device comprising: an innerglove (1) wearable under a martial art glove; one or more impact sensors(2) provided on the inner glove (1); and at least one unit (51)transmitting signals detected by the one or more impact sensors (2) to aremote station.
 2. The device according to claim 1, further comprisingone or more inertial sensors (3) coupled to the inner glove.
 3. Thedevice according to claim 1, further comprising one or more biometricsensors (4) coupled to the inner glove.
 4. The device according to claim1, wherein one or more fingers of the inner glove (1) are truncated,such that the inner glove (1), in a worn condition, covers only a firstphalange of one or more of corresponding fingers of a user.
 5. Thedevice according to claim 1, wherein said impact sensors (2) arepiezoelectric sensors.
 6. The device according to claim 1, wherein aplurality of said impact sensors (2) is provided, the impact sensorsbeing arranged to form an array.
 7. The device according to claim 6,wherein the plurality of impact sensors (2) are provided at aforefinger, middle finger, ring finger and little finger respectively.8. The device according to claim 7, wherein there are provided threeimpact sensors (2) for each one of the forefinger, middle finger, ringfinger and little finger.
 9. The device according to claim 7, whereinthe unit transmitting the signals transmits the signals to the remotestation in real-time.
 10. The device according to claim 1, wherein thedevice is powered by a rechargeable battery, there being provided arecharging circuit comprising an inductive charging system.
 11. Thedevice according to claim 1, further comprising a central processingunit (5), to which said sensors (2, 3, 4) are connected, the processingunit (5) being composed of a flexible electronic card.
 12. The deviceaccording to claim 4, wherein said one or more inertial sensors comprisean accelerometer,. and wherein the device is switched to stand-byconsequently to an inactivity period as detected by the accelerometer,and the device is switched on again once a movement is detected.
 13. Awearable device comprising: a plurality of impact sensors (2); and atleast one unit (51) transmitting signals detected by the plurality ofimpact sensors (2) to a remote station, wherein the plurality of impactsensors are arranged to form an array.
 14. The wearable device accordingto claim 13, wherein the device is composed of a glove or an inner glove(1).
 15. The wearable device according to claim 13, wherein the deviceis composed of a shin guard, a vest, a knee-pad, an elbow guard, ahelmet, or a shoe.
 16. The wearable device according to claim 13,further comprising one or more biometric sensors coupled thereto.
 17. Amethod of measuring power of an impact of a wearable device comprisingone or more impact sensors (2) and at least one accelerometer, whereinthe method comprises the following steps: (a) acquiring signals ofacceleration from the accelerometer; (b) obtaining a velocity vectoralong a predetermined direction by integrating the acceleration signals;(c) obtaining a force vector of the impact from the impact sensors, saidimpact sensors being positioned in such a way that the force vector isalong the predetermined direction of the velocity vector; and (d)calculating the power of the impact as a dot product of the force vectorand the velocity vector.
 18. The method according to claim 17, whereinthe velocity vector is taken into account for calculation of the powerof the impact only in a time period when velocity is decreasing duringthe impact.
 19. The method according to claim 17, wherein a low-passfilter is applied to the acceleration signals before step (b). 20.(canceled)